The invention relates to a planning device for generating control data for a treatment apparatus for cornea transplantation, said apparatus using a laser device to separate, by at least one cut surface in the cornea, a corneal volume from the surrounding cornea, which corneal volume is to be removed, and to separate, by at least one cut surface in a transplantation material, a transplant from the surrounding transplantation material, which transplant is to be inserted into the cornea.
The invention further relates to a treatment apparatus for cornea transplantation, which comprises a planning device of the aforementioned type.
Further, the invention relates to a method of generating control data for a treatment apparatus for cornea transplantation, which apparatus uses a laser device to separate a corneal volume, which is to be removed, from the surrounding cornea by at least one cut surface in the cornea and to separate a transplant, which is to be inserted into the cornea, from a surrounding transplantation material by at least one cut surface in the transplantation material.
Finally, the invention also relates to a method for cornea transplantation, wherein a treatment apparatus comprising a laser device is used to separate a corneal volume, which is to be removed, from the surrounding cornea by at least one cut surface in the cornea and to separate a transplant, which is to be inserted into the cornea, from a surrounding transplantation material by at least one cut surface in the transplantation material.
It has been known for a long time in ophthalmic surgery to correct changes in the cornea by means of transplantations. The term “transplantation” is understood in this context and also in the following description in the broadest sense, i.e. it comprises an allogenic transplantation, in which the cornea donor and the recipient belong to the same species, i.e. human cornea is transplanted. However, the term also comprises xenogenic transplantation, wherein animal cornea is implanted in the human eye. Further, the term also comprises alloplastic transplantation, wherein artificial material is implanted. The latter is often referred to also as implantation. Further, said term comprises a transplantation, wherein biotechnologically produced cornea (e.g. from stem cells) is used.
It has been known for a long time in the state of the art to carry out transplantations of cornea by cutting a corneal volume to be removed out of the cornea and replacing it with a transplant having, if possible, the same size. In this connection, US 2006/0020259 A1 discloses that the conventional cutting by a knife can be replaced by the use of a treatment apparatus comprising a laser, so that cutting is effected in a contact-free manner by laser radiation.
In addition to healing corneal diseases, transplantations are also known in the state of the art for correction of eyesight defects. In this connection, reference is made especially to WO 03/005920 A1, which teaches to form a pocket in the cornea, into which pocket a transplant is then inserted. The optical effect of the transplant is such that a desired correction of an eyesight defect is achieved thereby. This document also describes it as advantageous to use a laser radiation treatment apparatus to generate the pocket, which is, of course, adapted to the dimensions of the implant.
The already mentioned US 2006/0020259 A1, which intends to replace damaged or diseased cornea by way of transplantation, discloses that a cavity is generated in the cornea by means of laser radiation according to a predetermined cutting pattern. Next, a piece of cornea having, if possible, identical dimensions is cut out of the donor material by laser radiation and is then inserted into the previously generated cavity. The US document describes it as essential for the generated cavity and the cut-out piece to be identical, if possible, and a certain oversize of the transplant is regarded as advantageous for the transplant to be placed in the cavity as securely as possibly. In this case, the US document starts out from a predetermined cutting pattern for the cavity and allows the surgeon to perform minor modifications while cutting the transplant.
Based on a pre-set shape of the cavity, the surgeon can, thus, design the transplant such that its dimensions vary slightly, in order to achieve optimum in-growth of the transplant into the cornea of the recipient.
WO 03/005920 A1, also already mentioned, takes a slightly different approach as compared to the US document, because in the latter, the size of the implant which consists of an artificial material in the WO document, is already fixed and the cavity as well as a required insertion channel are cut to match the given implant.
In both cases, the cut surfaces in the eye are produced by known laser technology using an optical effect of laser radiation in the cornea, for example, by producing an optical breakthrough.
In this case, pulsed laser radiation is usually applied. It is also known to introduce individual pulses, whose energy is below a threshold value for an optical breakthrough, into the tissue or material in a superimposed manner such that a separation of material or tissue is achieved thereby as well.
This concept of producing cuts in the corneal tissue allows a large variety of cuts. The treating surgeon, therefore, theoretically has very great freedom in selecting the cut. However, this does not apply to the approach of WO 03/005920, because the implant to be inserted therein automatically defines the cut surface. According to said reference, the implant is first exactly measured, which then automatically results in the shape of the pocket to be generated for the implant in the cornea, and, thus, inevitably also yields the cut surface in the cornea. US 2006/0020259 A1 does not relate to the shape of the cut at all, but merely refers to a “predetermined cutting pattern”. Also, in this reference, the geometry of the cornea of both the recipient and the donor is the same; therefore, the control parameters of the laser device are also identical.